Instrumenting Transaction Trace Properties in Smart Contracts: Extending EVM for Real-Time Security

Abstract

In the realm of smart contract security, smart contracts can be instrumented with simple safety properties to enhance their security. However, these instrumentable safety properties are limited and fail to block certain types of hacks. This limitation primarily stems from the Ethereum Virtual Machine’s (EVM) inability to allow a smart contract to access the complete transaction trace in real-time. On the other hand, transaction malice detection methods can leverage properties of complete transaction traces to identify hacks with high accuracy. To bridge this gap, we propose modifications to both the EVM and Ethereum clients, enabling smart contracts to access the complete transaction trace and define and validate complex transaction trace properties in real-time without affecting traditional EVM execution. We use past-time linear temporal logic (PLTL) to express transaction trace properties, showcasing that most existing detection metrics can be expressed using PLTL.